Abstract: The suitable model compounds were selected base on the analysis of hydrocarbon compositions of LCO to investigate the extraction effect of solvent on aromatic compounds in LCO and the relationship between solvent extraction performance and solvent physical parameters. It was found that the order of the selectivity coefficient of the studied solvents to aromatics was sulfolane> DMSO > furfural > DMF > NMP > DMAC. The dipole moment and dielectric constant of the solvent should be sufficiently different from those of the hydrocarbons in LCO in order to effectively separate the aromatic hydrocarbons in LCO. The selectivity coefficient of solvent to aromatics can be correlated with its solubility parameter. For the solvent with δD（dispersion force parameter, one of the solubility parameters）close to that of aromatics, the larger δP (polarity force), the better the selectivity coefficient to aromatics. At 40 ℃ and oil-mass ratio 1:1, the total aromatics mass fraction in the extracted oil obtained by DMF was only 87.2% in a single pass, while that of sulfolane was 97.3%. By introducing co-solvent into DMF to enhance δP, the total aromatics mass fraction and yield of extracted oil reached 96.5% and 29.9%, respectively under the same conditions.

Key words: light cycle oil, extration, solvent, solubility parameter, aromatics